Portable boring machine



July 14, 1931. F. s. HARTWELL PORTABLE BOBIN Filed Sept. 14, 1926 3 Sheets-Sheet 1 July 14,1931. F. s. HARTWELL PORTABLE BORING MACHINE Filed Sept. 14, 1926 3 Sheets-Sheet 2 k g INVENTOR.

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July 14, 1931 F. s. HARTWELL PORTABLE BORING MACHINE Filed Sept. 14, 1926 5 Shoots-Sheet 3 Patented July 14, 1931 UNITED STATES FLOYD S. HARTWELL,

OF CLEVELAND, OHIO PORTABLE BORING MACHINE Application filed September 14, 1926. Serial No. 135,407.

This invention relates to boring or reaming bars especially adapted for use in providing smooth, round bores in the cyllnders of air compressors, although not restricted II to such use.

Briefly stated, an important obJect of the invention is to provide novel and slmply operated means by which a reamer may be properly positioned and held 1n lme to ream or bore the cylinders of an air compressor even though the main bearings of the com pressor which receive the forward p1lot trunnions may be slightly above or below the center lines of the cylinders.

A further and equally important ob3ect is to provide a reamer in which the shank thereof is provided with a 11I1lV8I'S3Ll ]0lI1t so that in case the driving element 1s not positioned in exactly the right place the shank of the cutter will not be dlscarded and the reamer caused to make an untrue out.

Other objects and advantages will be apparent during the course of the followlng description.

In the accompanying drawlngs formmg a part of this application and 1n wh1ch l ke numerals are employed to designate like parts throughout the same,

Figure 1 is a side elevatlon of the 1mproved rotary cutter applled, the forward pilot thereof being shown in sect on;

Figure 2 is a horizontal sectlonal v1ew through the forward pilot mechanism;

Figure 3 is a vertical transverse sectronal view through the forward pilot mechanism;

Figure 4 is a perspective of a rear p1lot embodied in the invention;

Figure 5 is a perspective of a centermg bar embodied in the invention; I

Figure 6 is a sectional view through a compressor, the view illustrating the improved means by which the forward pilot is proper- 1y positioned preparatory to the application of the rotary cutter.

In the drawings wherein for the purpose of illustration is shown a preferred embodi ment of the invention, the numeral 5 desig- 0 nates the crank case of an air compressor and the numerals 6 designate the cylinders of the air compressor.

Reference to Figure 6 will clearly show that the crank case is provided with alined bearings 7 to receive the journals of a crank shaft not shown. A line extending centrally through the bearings 7 will, of course, be exactly at a right angle to the axes of the cylinders 6, but such line may not bisect the locomotives are equipped with a motor driven air compressor, usually of the twin cylinder or duplex type.

These compressors may run from two to four years on a street car or locomotive and then have to be removed and given a thorough overhauling. A part of the overhauling operation consists in refinishing the piston receiving cylinders. If the system is that of reaming to standard oversizes the practice followed is to ream the first time to .010. The second time the cylinder is reamed to .020". The third ream is to .030 and so on until the cylinders have been reamed oversize after which the cylinders are bored to oversize and a cast iron bushing with a flange fitted into the outer face of the cylinder is pressed into the cylinder and the inside bore reamed back to the original diameter of the cylinder.

It might be added that no satisfactory system has so far been devised to enable the street car repair men to properly ream or bore these cylinders in their own shops. As a result they have sent the air compressors to outside concerns which specialize in re grinding automobile cylinders and the cylinders of the air compressors are ground at approximately $12 each if the cylinder is approximately 4.750 in diameter.

To further explain the difficulties in the way of the successful refinishing of the cylinders, it might be added that in the process of manufacture of an air compressor the bearings for the reception of the ournals of the crank shaft are at perfect right angles to the cylinder bores and parallel with the flat bottom milled surfaces of the securing lugs or feet by which the compressor may be secured to the street car or locomotive.

It is a comparatively simple matter to extend the bearings for the crank shaft exactly at right angles to the axes ofthe cylinders, but a line extending centrally through the bearings may not absolutely coincide with a line bisecting the centers ofboth cylinders. In other words, the crankshaft when applied may be g above the center line of the cylinders or below the center lines of the cylinders without affecting the operation of the efliciency of the compressor. \Vhile this difference does not affect the operation of the compressor, it is a great disadvantage when reboring or re-reaming the cylinders, especially if pilot guides are to be fastened into the crank shaft bearings for the reception of the forward pilot of the learner or boring bar.

As previously stated, it is an object of this invention to provide simple and easily adjusted means whereby the rotary cutter, be it a boring or reaming bar, may be properly positioned for making the desired out even ihough the center line of the bearings of the compressor is above or below a line bisecting the axes of the cylinders.

11 carrying out the invention a boring bar or reaming bar head 10 is provided with a shank 11, the rear portion of which may be provided with a universal joint 12 by which the shank and the cutter head may operate undisturbed even though there is an irregularity in the drive as will be appreciated.

With reference to Figure 1, it will be observed that a rear pi-lot 16 is provided with an elongated sleeve 17 to receive and guide the shank 11 of the cutter. The pilot 16 is provided with attaching flanges 19 adapted 'to be secured by bolts to one of the annular flanges 20 of the cylinders of the air compressor. lVhen the rear 'pilotis applied the shankll and thecut'ter head will be accurately piloted through the cylinder to make a proper cut as will be described. Of course, a forward pilot to be described in detail effectively cooperates in holding the cutter head in position while the cutter head is turning.

The cutter head 10 is provided with an integral pilot bar 26 adapted to be selectively extended into locati bushings 28, the forward portions of whi c h are threaded into the attaching members 29.

In carrying out the invention the attaching members 29 are made rectangular in outline and'are adjustably carried by a locating block 32. The locating block 32 consists of top and bottom plates 33, end trunnions 34 having attaching portions 36 secured between the plates 33 by cap screws 37 or other suitable fastening devices. A partition block 35, secured by screws has opposite faces in fiat contact with plates 33 and its sides are spaced equidistant fromportions 36.

Figure 3 clearly illustrates that the attaching portions 29 of the locating bushings 28 may be moved in the direction of the plates 33 by set screws 40 carried by the plates 33 and having their forward ends engaged with oppositesides of the attaching portions 29. Suitable lock nuts 46 may be employed to secure the set screws in position. It, is believed to be clear that the set screws 40 provide a means whereby the pilot bushings or locating bushings 28 may be properly positioned with respect to the cylinders 6 to be finished or refinished even though the crank bearings 7 which receive the trunnions 34 are above or below center with respect to the axes of the cylinders.

Particular attention is directed to Figures 2 and 3 which clearly illustrate that tongue and groove connections 50 hold the attaching portion 29 against endwise movement between partition 3; and end walls 36 in the locating block, but at the same time permit the attaching portion to be moved toward walls 33 under the influence ofthe set screws 40. Y

In use, the locating block is applied as illustrated in Figure-6 and a centering disc 60 and a centering stem 61 having a tapered plug 62 are applied to one of the cylinders. More specifically, the disc 60 is positioned in the forward portion of one of the cylinders and the plug 62 is then introduced into that {1505 cylinder so that the stem 61 extends through the centrally arranged opening in the disc 60. When the stem is applied as shown in Figure 6 the locating bushings 28 which receive the forwardiportion of the stem 61 will CEO be properly positioned, after which it may be secured in place by the associated set screws 40.- When one of the locating bushings 28 has been properly positioned and locked in place preparatory to the use of the rotary cutter, the stem 61 and the disc 60 are removed and applied to the other cylinder for adjusting its locating bushing 28, after which the second locating bushing 28 may be locked in place by the associated set Q20 screws 40. lVhen the two bushings "28 have been locked in place the caps ofthebearings 7 may be fastened lightly in place to hold the trunnions 34 and the reaming or boring ope-rations started. During the ream- 3.25 ing or boring operation in one cylinder the stem 61 and associated parts is allowed to remain in the other cylinder. Infact when it is desired to ream'the second cylinder the stem 61 is removed from that cylinder and I30 placed in the cylinder just reamed so as to be sure of an absolutely accurate cut.

Having thus described the invention, what is claimed is:

1. A cylinder boring device adapted for the machining of a crank case having a plurality of cylinders and opposed crank shaft bearings'whose axes are alined in a plane at right angles to the axes of the cylinders, said device comprising a rotary cutter having a forwardly extending pilot, a locating block having trunnions adapted to be secured in said bearings, carriers slidably mounted in said block and substantially alined with the respective cylinders, said carriers being independently adjustable in a plane at right angles to the axes of their respective cylinders, said carriers having guide means to receive said pilot, and centering means positionable in one of said cylinders to engage in the guide of the carrier associated therewith whereby to hold the locating block in a set position at right angles to the axes of the cylinders while another cylinder is being bored.

2. The combination set forth in claim 1 and said guide means of said carriers comprising a sleeve threaded thereinto, and the carriers having a bore communicating with the bore of said sleeve.

3. A cylinder boring device adapted for the machining of a crank case having a plurality of cylinders and opposed crank shaft bearings whose axes are alined in aplane at right angles to the axes of thecylinders, said device comprising a rotary cutter, having a forwardly extending pilot, a locating block having trunnions adapted to be secured in said bearings, carriers slidably mounted in said block and substantially alined in one direction with the respective cylinders, said carriers being independently adjustable in a plane at right angles to the axes of their respective cylinders, said carriers having guide bushings extending laterally of the axis of the bearings and toward the cylin ders, and centering means positionable in one of said cylinders to engage in the guide bushing of the carrier associated therewith whereby to hold the locating block in set position at right angles to the axes of the cylinders while another cylinder is being bored.

In testimony whereof I aflix my signature.

FLOYD S. HARTWELL. 

